This proposal seeks support for hiring a young husband and ife team from the HHMI Janelia Farm Research Campus who will add great strength to the Vollum Institute. Drs. Haining Zhong and Tianyi Mao utilize newly developed optical approaches to solve problems involving neural circuits and signaling, an area complementary to the Vollum's existing strengths. Dr. Zhong recently completed his postdoctoral fellowship with Karel Svoboda and Eric Betzig, co-inventor of photoactivated localization microscopy (PALM). Dr. Mao also did her postdoctoral fellowship in the Svoboda lab. Our intent is to use these PSO funds to help offset the costs of their sophisticated microscopic needs so that the available start up funds can be used for longer term commitment. These two investigators will have extensive intersections with existing Vollum faculty, and there is widespread excitement at the prospect of hiring them. PSO funds are critical for insuring their successful transition to independence. Traditional electrophysiological and biochemical approaches, although powerful in addressing many questions, lack the necessary spatiotemporai resolution for addressing key questions. Dr. Zhong utilizes newly developed imaging methodologies that extend beyond the diffraction limit of conventional light microscopy to explore signaling pathways at the synapse. He will develop methods to combine PALM with electron microscopy to analyze the regulation of PKA localization in synaptic spines and use two-photon fluorescence lifetime imaging (FLIM) to measure direct interaction of PKA with associated proteins.Dr. Mao also uses advanced imaging techniques, together with molecular and physiology tools such as laser scanning photostimulation (LSPS), channelrhodopsin-assisted circuitry mapping (CRACM), and genetically encoded calcium sensors to map local circuits underlying reward-related behaviors in the basal ganglia. She initially will focus on comparing how the inputs from various areas of the cortex and the thalamus differentially influence striatal neuronal activities within and between different compartments. A longer-term goal will be to characterize circuit changes through different stages of behavior {e.g., goal-directed vs. habitual) as animal models of addiction. This set of recruitments would allow the Vollum to further its preeminence in synaptic modulation and signaling, the central focus of its program, and extend into the area of neuronal circuitry.